DOUBLE CLUTCH UNIT AND DRIVE ARRANGEMENT WITH SUCH A DOUBLE CLUTCH UNIT

Description

[0001] The invention relates to a dual-clutch unit for variable torque distribution across two output shafts, according to the preamble of claim 1, comprising an outer disk carrier rotatably driven about a rotational axis, a first inner disk carrier, a first disk set for transmitting torque between the outer disk carrier and the first inner disk carrier, a second inner disk carrier, the first inner disk carrier and the second inner disk carrier being arranged to rotate relative to one another about the rotational axis, and a second disk set for transmitting torque between the outer disk carrier and the second inner disk carrier. Furthermore, the invention relates to a drive arrangement for driving a drive axle of a motor vehicle having such a dual-clutch unit.

[0002] However, the friction-disk clutches or multi-disk clutches used are components that are exposed to high temperatures during motor vehicle operation. Especially in clutch packs consisting of multiple discs, the so-called inner and outer discs, cooling of the friction discs with a coolant and / or lubricant is necessary.

[0003] From US 2 935 889 A, a dual clutch unit for transmitting torque from two input shafts to one output shaft is known. The dual clutch unit comprises: an outer clutch disc carrier which is driven to rotate about a rotational axis and is connected to the output shaft; a first inner clutch disc carrier and a second inner clutch disc carrier, wherein the first inner clutch disc carrier and the second inner clutch disc carrier are arranged to rotate relative to one another about the rotational axis. The first inner clutch disc carrier comprises a first distribution channel, and the second inner clutch disc carrier comprises a second distribution channel. The first inner clutch disc carrier further comprises a through-bore which fluidically connects the second distribution channel to the first distribution channel. The through-bore has the shape of a straight cylinder parallel to the axis of rotation is arranged.

[0004] US Pat. No. 3,734,259 A discloses a dual clutch unit comprising an outer clutch disc carrier, a first inner clutch disc carrier supporting one clutch disc, and a second inner clutch disc carrier supporting two clutch discs. Openings are provided in each of the clutch discs.

[0005] US 2006 / 113157 A1 discloses a single clutch disc carrier for a multi-disk clutch, which has an outer cylindrical part with grooves formed on the outer circumference. An inner circumferential surface is formed on the inner circumference of the outer cylindrical part. The inner circumferential surface defines a space divided into two conical halves by a wall. The wall extends radially from the outer cylindrical part toward an inner cylindrical hub portion. A through-bore is formed in the hub portion.

[0006] US 2018 / 058513 A1 discloses an arrangement for the controlled cooling and / or lubrication of clutch plate packs arranged in a housing. The housing comprises a central partition wall comprising a radial wall and a central hub. The partition wall separates the housing into two internal chambers in which the plate packs are arranged. Each plate pack can comprise nested plates, such as separator plates that are attached or toothed to the housing at their outer periphery, and friction plates that are nested with the separator plates and toothed to the hubs at their inner periphery.

[0007] WO 2017 / 157479 A1 discloses a dual clutch unit for variable torque distribution across two output shafts. The dual clutch unit has two friction clutches, each of which is assigned its own clutch lubrication line.

[0008] EP 1 664 567 B1 discloses a dual clutch unit in which a common inner disk carrier is driven and two outer disk carriers are arranged to rotate independently of each other around the common axis of rotation. The two disk packs are supplied with coolant and / or lubricant via lubricating oil channels integrated into the common inner disk carrier. Via an oil channel formed as an extension between the two disk packs in the inner disk carrier, the coolant and / or lubricant is guided from the hub, radially outward into axially extending annular channels, and finally into the two disk packs.

[0009] The object of the invention is to provide a dual clutch unit of the type mentioned above which can absorb very high forces with minimal installation space and wear and which can also withstand continuous operation with slip.

[0010] This object is achieved in that, in the double clutch unit of the type mentioned at the beginning, a borehole longitudinal axis of the at least one through-bore encloses a bore angle with the rotation axis.

[0011] The coolant serves to cool and / or lubricate the disk packs, so it could also be referred to as a coolant and / or lubricant. Typically, an oil-based coolant is used for this purpose.

[0012] The first distribution channel thus has a dual function: first, supplying the first plate pack with coolant, and second, partially forwarding the coolant to the second distribution channel. The second distribution channel is thus positioned downstream of the first distribution channel in the direction of coolant flow. Accordingly, the coolant coming from the central oil supply initially flows through the first distribution channel, and only a portion of the coolant is forwarded through the first distribution channel to the second distribution channel. The two distribution channels are thus connected in series. Connecting the two distribution channels in series, one behind the other in the direction of coolant flow, results in a compact dual clutch unit.

[0013] Preferably, the first distribution channel can be supplied with coolant via a lateral access. For this purpose, the inlet opening can be formed on an end face of the first inner disk carrier facing away from the second inner disk carrier. The inlet opening can be an annular opening arranged concentrically to the rotational axis.

[0014] The first distribution channel is formed in the first inner plate carrier and the second distribution channel is formed in the second inner plate carrier. The two inner plate carriers are arranged to be rotatable relative to one another about the common axis of rotation, for example in a clutch housing, so that when the dual clutch unit is in operation, the two inner plate carriers can rotate about the axis of rotation at different speeds depending on the driving condition. In order to fluidly connect the first distribution channel to the second distribution channel even when there are differences in speed, a rotary feedthrough can be provided. For this purpose, the first inner plate carrier can have an axial projection with at least one through-bore. Axial means in the direction of the axis of rotation, or along the axis of rotation, in particular parallel to the axis of rotation.Preferably, the second distribution channel is fluidly connected to the first distribution channel via the at least one through-bore. Accordingly, it can be provided that the coolant coming from the central oil supply first flows through the first distribution channel, and a portion of the coolant is passed through the at least one through-bore into the second distribution channel.

[0015] Preferably, several of the through-bores extend through the projection, in particular two, three, four, five, six or more than six through-bores. The through-bores can be arranged distributed in the circumferential direction around the axis of rotation. The at least one through-bore can each have an outlet opening on an end face facing the second distribution channel. The projection expediently projects into the second distribution channel. The at least one through-bore can thus open directly into the second distribution channel on the outlet side in the flow direction. The first distribution channel can open directly into the at least one through-bore on the inlet side in the flow direction. An outer diameter of the projection can preferably be smaller than an outer diameter of the second distribution channel or equal to the outer diameter of the second distribution channel.An inner diameter of the projection can be larger than an inner diameter of the second distribution channel or equal to the inner diameter of the second distribution channel. The second distribution channel is expediently designed as an annular gap extending in the axial direction, at least in an area of ​​axial overlap with the projection, i.e. along the area in which the projection projects into the second distribution channel. In this way, the two inner disk carriers can rotate relative to one another about the axis of rotation. As a result, the projection of the first inner disk carrier, with the at least one through-bore, and the second distribution channel, in the area of ​​axial overlap with the projection, together form the rotary feedthrough.

[0016] The first inner plate carrier and the second inner plate carrier are preferably supported axially against one another. This results in a particularly narrow overall width. A spacer can be arranged axially between the two inner plate carriers. The spacer can be an annular body arranged concentrically to the axis of rotation and the two inner plate carriers. Due to the speed differences between the two inner plate carriers, which can occur during operation of the dual clutch unit, the spacer preferably has a sliding surface. The spacer can be pushed onto the projection of the first inner plate carrier. Furthermore, the spacer can assume a sealing function and seal the transition between the first inner plate carrier and the second inner plate carrier radially outwards. Radial means along an axis that lies in a plane perpendicular to the axis of rotation.The spacer can in particular be made of a bronze material, a bronze-based material, a sintered material, in particular sintered bronze or the like.

[0017] According to one aspect of the present invention, the first distribution channel and / or the second distribution channel can each be designed as an annular gap extending in the axial direction and arranged concentrically to the axis of rotation. Due to the centrifugal forces, the coolant is pressed against a radially outer channel wall of the respective distribution channel. As an alternative to designing the first distribution channel and / or the second distribution channel as an annular gap, the first inner disk carrier and / or the second inner disk carrier can have a plurality of distribution channels arranged distributed in the circumferential direction around the axis of rotation. Thus, a plurality of the first distribution channels and / or a plurality of the second distribution channels can be provided. The distribution channels can each be designed as bores that extend in the axial direction.In order to convey the coolant during rotation of the respective inner plate carrier, the distribution channels designed as bores can run obliquely to the axis of rotation. In particular, borehole longitudinal axes formed by the distribution channels can each enclose an angle with the axis of rotation. The angle can be between 0.01° and 10°. The respective angle preferably opens in the direction of flow of the coolant. The borehole longitudinal axes of the distribution channels can enclose the same angle with the axis of rotation. In principle, the angle of the borehole longitudinal axes of the distribution channels in the first inner plate carrier can also differ from the angle of the borehole longitudinal axes of the distribution channels in the second inner plate carrier to the axis of rotation.

[0018] Expediently, outlet openings are formed in the radially outer channel wall of the first distribution channel and in the radially outer channel wall of the second distribution channel, which open into the outlet channels of the respective inner plate carrier. Particularly good results with regard to uniform cooling and / or lubrication of the two plate packs have been achieved when the outlet openings are formed on an imaginary spiral arranged concentrically to the axis of rotation. During operation of the dual clutch unit, it has been shown that the supply of coolant via the inlet opening of the first distribution channel formed on the side of the first inner plate carrier can lead to an oversupply of the first plate pack. In order to adapt the coolant supply locally, the diameter of the outlet openings in the first plate carrier and in the second plate carrier can be varied. In particular, the diameter of the entire outlet channels can be varied.Furthermore, at least a subset of the outlet openings or outlet channels in the first distribution channel can have a smaller diameter than at least a subset of the outlet openings or outlet channels in the second distribution channel. The outlet channels preferably extend in a radial direction.

[0019] Furthermore, a circumferential surface radially outwardly bounding the first distribution channel and / or a circumferential surface radially outwardly bounding the second distribution channel can be truncated cone-shaped. The axis of the respective truncated cone is preferably the common axis of rotation about which the two inner disk carriers and the outer disk carrier are rotatably arranged. The respective distribution channel, in particular one in the form of an annular gap, preferably widens radially outwards in the direction of flow of the coolant. Due to the increasing distance of the radially outer circumferential surface in the axial direction, the coolant is conveyed through the respective distribution channel by the centrifugal force on the radially outer channel wall, in a direction away from the inlet opening. In particular, an opening angle between the surface lines of the respective circumferential surface and the axis of rotation is between 0.01° and 10°.The respective opening angle preferably opens in the flow direction of the coolant.

[0020] Instead of the respective distribution channel expanding radially in the axial direction, the respective radial outer channel wall of the first distribution channel and / or the second distribution channel can also be aligned parallel to the axis of rotation. An Archimedean screw can be arranged in each respective distribution channel. The Archimedean screw can convey the coolant in the respective distribution channel like a worm pump when the respective inner disk carrier rotates. The respective Archimedean screw is connected in the associated distribution channel to the first inner disk carrier or the second inner disk carrier in a rotationally fixed manner.

[0021] Preferably, the second distribution channel is closed at an axial end facing away from the first inner disk carrier. Thus, the coolant can preferably leave the second distribution channel exclusively via the outlet channels.

[0022] Preferably, the coolant can exit the first distribution channel exclusively via the outlet channels in the first inner disk carrier and via the at least one through-bore. The outlet channels preferably adjoin the associated distribution channel and are arranged radially between the respective distribution channel and the associated disk pack.

[0023] Furthermore, guide means for directing a portion of the coolant to the at least one through-bore can be formed in the first distribution channel. This ensures that a portion of the coolant always arrives in the second distribution channel, which is arranged downstream of the first distribution channel in the flow direction, in order to avoid an undersupply of the second plate pack or an oversupply of the first plate pack. The guide means can have at least one, in particular elongated, depression, such as a groove, channel, trough or the like. In particular, the at least one depression has a constant depth over its length. The at least one depression can be formed in the radially outer channel wall of the first distribution channel. The at least one depression can extend over at least 20% of the axial longitudinal extent of the first distribution channel.Preferably, the at least one recess extends over more than 70% of the longitudinal extent of the first distribution channel, wherein the at least one recess can extend over the entire longitudinal extent of the first distribution channel. The at least one recess can open into the at least one through-bore. Advantageously, each through-bore is assigned its own recess. For example, the first inner disk carrier can have a plurality of through-bores arranged in the circumferential direction, in particular two, three, four, five, six or more through-bores, wherein exactly one recess can open into each through-bore. Thus, the number of through-bores and the number of recesses can be the same.

[0024] Conveniently, the at least one through-bore adjoins the radially outer channel wall, in particular the associated recess, to provide a smooth transition between the first distribution channel and the at least one through-bore. A borehole longitudinal axis of the at least one through-bore can enclose a bore angle of between 0.01° and 10° with the rotation axis. In particular, the bore angle and the opening angle of the surface lines of the lateral surface of the first distribution channel are identical.

[0025] The outer plate carrier preferably has a plurality of drainage channels for draining the coolant. The coolant discharged from the radial inside via the outlet bores of the inner plate carrier is guided through the plate packs by centrifugal forces, cools and / or lubricates the individual plates, and finally reaches the outer plate carrier, where it can be drained radially outwards via the drainage channels. At least a subset of the drainage channels along the first plate pack can have a smaller diameter than at least a subset of the drainage channels along the second plate pack. In this way, the drainage amount of coolant supply can be locally adjusted to achieve even lubrication of both plate packs. The coolant draining from the outer plate carrier can flow via a housing wall of a clutch housing of the dual clutch unit, for example, into a sump in the clutch housing.There, it can be fed to the central oil supply via a pumping device. The pumping device can be, in particular, a pump or a rotating gear with a scraper, whereby the gear can be immersed in the sump and the scraper can scrape off the coolant.

[0026] Furthermore, the dual clutch unit can have a deflection ring. The deflection ring can be fluidly connected, in the flow direction, to the central oil supply on the inlet side and to the first distribution channel on the outlet side. The deflection ring can be arranged concentrically to the axis of rotation. Preferably, the deflection ring is inserted or pressed into a recess in a clutch housing and is held stationary relative to the clutch housing. Thus, during operation of the dual clutch unit, the deflection ring does not rotate about the axis of rotation, but remains stationary. The deflection ring can have a collecting groove that is open in the circumferential direction and a plurality of transfer bores distributed in the circumferential direction, which are at least substantially axially aligned and fluidly connected to the collecting groove.During operation, the coolant supplied radially outside the deflection ring can flow around the deflection ring in the collecting groove and exit the deflection ring axially via the transfer holes. This enables an axially compact design. The deflection ring can be a plastic part, for example, in particular an injection-molded plastic part, although metallic materials are also possible.

[0027] Furthermore, a cover can be arranged on the side of the outer disk carrier in a rotationally fixed manner. At least one transfer bore can be formed in the cover, which fluidly connects the at least one transfer bore of the deflection ring to the first distribution channel. During operation of the dual clutch unit, the cover rotates together with the outer disk carrier about the axis of rotation. Due to the speed differences compared to the stationary deflection ring, a rotary feedthrough can be provided for fluid communication. For example, the cover can have a plurality of transfer bores distributed in the circumferential direction around the axis of rotation, wherein the transfer bores of the cover and the transfer openings of the deflection ring can be arranged in such a way that they are temporarily fluidly connected to one another at least once during one rotation of the cover about the axis of rotation.In order to seal the fluid transfer between the deflection ring and the cover, the deflection ring can engage in an annular gap that is open towards the deflection ring. The cover, in turn, can have an axial projection that projects into the first distribution channel to seal the fluid transfer between the transfer bores and the first distribution channel. The first distribution channel is designed as an annular gap extending in the axial direction, at least in an area of ​​axial overlap with the projection of the cover, i.e. along the area in which the projection projects into the first distribution channel. In this way, the cover, which is connected in a rotationally fixed manner to the outer disk carrier, and the first inner disk carrier can rotate at different speeds about the axis of rotation.Since speed differences can also occur between the cover and the first inner disk carrier, a rotary union can also be provided here for fluid communication. Instead of the described arrangement of the cover between the deflection ring and the first inner disk carrier, the deflection ring can also protrude directly into the first distribution channel, so that a rotary union can be formed by the axially overlapping areas of the deflection ring and the first inner disk carrier.

[0028] The torque can be transferred between the outer disk carrier and the respective inner disk carrier in both directions. During normal operation, a drive motor rotates the outer disk carrier so that the torque can be transferred from the outer disk carrier via the first disk pack to the first inner disk carrier and / or via the second disk pack to the second inner disk carrier. When using a generator in the drive train, for example an electric drive that can operate as both a motor and a generator, the torque flow can be reversed for energy recovery so that torque can be transferred from the first inner disk carrier via the first disk pack and / or from the second inner disk carrier via the second disk pack to the outer disk carrier.

[0029] The dual clutch unit enables variable torque distribution between the two output shafts, particularly of a motor vehicle. A differential gear for torque distribution between the two output shafts is therefore unnecessary. For variable torque distribution, the dual clutch unit can have two separately controllable friction clutches, whose transmittable torque can be individually adjusted. Depending on the driving conditions, the torque at an inside or outside wheel can be individually adjusted, which overall leads to improved driving dynamics and driving stability. When driving straight ahead, both friction clutches can be closed. Speed ​​compensation when cornering can then be achieved by slipping the friction clutches. The tighter the curve, the greater the slipping. If, on the other hand, the clutches are firmly closed, this corresponds to a 100 percent lock.Thus, the dual-clutch unit allows the drive power to be continuously controlled for each wheel. This control principle is also known as active torque distribution or "torque vectoring." This can be specifically utilized as part of a vehicle's dynamic tuning to mitigate an unwanted tendency to understeer by creating a positive yaw moment. Furthermore, vehicle dynamics can also be positively influenced by a controlled speed difference between the front and rear axles of the vehicle. Similarly, similar to a limited-slip differential, the two vehicle wheels can be connected to each other by synchronously controlling the clutch. This leads to significantly improved traction and can be used to dampen yaw at higher speeds.

[0030] A solution to the above-mentioned problem further consists in a drive arrangement for driving a drive axle of a motor vehicle, comprising: a drive motor with a motor shaft, two output shafts arranged concentrically to one another, and a clutch unit arranged in the power path between the drive motor and the two output shafts, which clutch unit is designed according to at least one of the above-mentioned embodiments. The motor shaft drives the outer disk carrier in rotation, and a first of the two output shafts is connected in a rotationally fixed manner to the first inner disk carrier, and a second of the two output shafts is connected in a rotationally fixed manner to the second inner disk carrier. The drive arrangement according to the invention results in the same advantages as the dual clutch unit according to the invention, so that reference is made to the above description in this regard.

[0031] Preferred embodiments are explained below with reference to the drawing figures. Herein: Figure 1 shows a dual clutch unit according to the invention in a first embodiment in longitudinal section; Figure 2 shows an enlarged partial section of the dual clutch unit according to Figure 1 ; Figure 3 an enlarged partial section of the double clutch unit according to Figure 1 in longitudinal section; Figure 4 the double clutch unit in cross section; Figure 5 a deflection ring in perspective view; Figure 6 the deflection ring from Figure 5 in side view; Figure 7 an enlarged partial section of the deflection ring from Figure 5 in longitudinal section; and Figure 8 shows an enlarged partial section of a double clutch unit according to a second embodiment in longitudinal section; Figure 9 shows an Archimedean screw from Figure 8 in longitudinal section; and Figure 10 shows an enlarged partial section of a dual clutch unit according to a third embodiment in longitudinal section.

[0032] The Figures 1 to 7, which are described together below, show a dual clutch unit 1 according to the invention according to a first embodiment, which can also be referred to as a clutch arrangement. The dual clutch unit 1 is used in particular in the drive train of a motor vehicle for variable torque distribution from an input part, here an outer disk carrier 2, to two output parts, here a first inner disk carrier 3 and a second inner disk carrier 4. The outer disk carrier 2 and the two inner disk carriers 3 are arranged so as to be rotatable about an axis of rotation X. The outer disk carrier 2 can, for example, be driven in rotation via a ring gear. For variable torque distribution, the dual clutch unit 1 has two separately controllable friction clutches 5, 6, the transmittable torque of which can be individually and variably adjusted.

[0033] This makes the dual clutch unit 1 suitable for actively controlling the yaw motion of the motor vehicle or its yaw angular velocity. This is achieved by differentially distributing or specifically adjusting the torque to a right output shaft, also referred to as the side shaft 50, and a left output shaft, also referred to as the side shaft 60, of a driven axle. Such systems for variable torque distribution are also referred to as "torque vectoring" systems or "active yaw" systems. The control principle is also referred to as active torque distribution or "torque vectoring."

[0034] The first inner disk carrier 3 is connected here to the right side shaft 50, and the second inner disk carrier 4 is connected to the left side shaft 60 of the driven axle in a rotationally fixed manner. Accordingly, the two inner disk carriers 3, 4 can also be referred to as clutch hubs.

[0035] The two friction clutches 5, 6 are arranged axially next to one another and concentrically to the rotational axis X. They are preferably designed identically in terms of their structure, in particular their geometric dimensions. Specifically, the friction clutches 5, 6 each have a plate pack 7, 8. The first plate pack 7 serves for variable torque transmission between the outer plate carrier 2 and the first inner plate carrier 3, while the second plate pack 8 serves for variable torque transmission between the outer plate carrier 2 and the second inner plate carrier 4. The two plate packs 7, 8 can be individually subjected to force, so that the torque to be transmitted to the respective side shaft 50, 60 can be precisely adjusted as required.For this purpose, the plate packs 7, 8 each comprise a plurality of outer plates which are non-rotatably and axially movable with the outer plate carrier 2, as well as a plurality of inner plates which are non-rotatably and axially movable with the associated inner plate carrier 3, 4, which are arranged axially alternately.

[0036] The two plate packs 7, 8 can each be axially biased toward one another by an associated pressure plate 9, 10 and are each axially supported by an associated support element 11, 12. The two support elements 11, 12, which are arranged axially between the two plate packs 7, 8, are in turn axially supported against the outer plate carrier 2. The support elements 11, 12 are ring-shaped and arranged concentrically to the rotation axis X. The two support elements 11, 12 engage axially with one another and are axially supported independently of one another against the outer plate carrier 2.

[0037] The dual clutch unit 1 has a clutch chamber 13, which is delimited radially on the outside by the outer disk carrier 2 and radially on the inside by the two inner disk carriers 3, 4. Furthermore, a right cover 14 and a left cover 15 are provided, which laterally delimit the clutch chamber 13. The two covers 14, 15 are connected in a rotationally fixed manner to the outer disk carrier 2 and each have a central opening 16, 17 for receiving the right and left side shafts 50, 60, respectively. A plain bearing is provided between the covers 14, 15 and the respective side shafts 50, 60. The first disk pack 7, the first support element 11, the second support element 12 and the second disk pack 8 are accommodated in the clutch chamber 13.

[0038] Each of the two friction clutches 5, 6 can be individually actuated by an associated actuator unit 18, 19. For this purpose, the two actuator units 18, 19 can be controlled independently of one another by means of a control unit (not shown), so that a first torque, which can be transmitted from the first disk pack 7 to the first inner disk carrier 3, and a second torque, which can be transmitted from the second disk pack 8 to the second inner disk carrier 4, can be variably adjusted independently of one another. The two actuator units 18, 19 are designed identically in terms of their structure and function.

[0039] The actuator units 18, 19 can be hydraulic or electric actuator units, in particular electro-hydraulic, electromotive, or electromagnetic actuator units. The actuators are each supported axially on a clutch housing 20 in opposite axial directions. The hydraulically operated actuators here each have an annular piston 21, which is axially displaceably seated in an associated annular cylinder chamber 22 of the clutch housing 20. An opening 23 is formed in each of the laterally arranged covers 14, 15 of the outer disk carrier 2, through which opening the respective piston 21 interacts with the associated pressure plate 9, 10 to actuate the respective friction clutch 5, 6. A hydraulic pump can generate hydraulic pressure via oil channels (not shown here), so that the respective piston 21 is moved axially toward the disk pack 7, 8.Return springs 24 are provided here to return the pistons 21.

[0040] The friction clutches 5, 6 are designed in particular as wet-running multi-plate clutches. For their fluid supply, the plate packs 7, 8 are supplied with coolant and / or lubricant, hereinafter referred to as coolant, which is discharged into the clutch chamber 13 via outlet channels 25', 25" formed in the inner plate carriers 3, 4. The coolant discharged from the radially inside is guided through the plate packs 7, 8 by centrifugal forces and discharged radially outward via drain channels 26 formed in the outer plate carrier 2. The respective channels 25', 25", 26 are preferably each arranged in a tooth base of a tooth gap of the inner plate carrier 3, 4 or the outer plate carrier 2. Accordingly, the outlet channels 25', 25" of the respective inner disk carrier 3, 4 can be axially offset from the outlet channels 26 in the outer disk carrier 2, as shown in Figure 3is shown. Due to an inclined upper side of the clutch housing 20, the coolant is drained downward into a sump 67. Furthermore, a conveying device (not shown) can be provided, which feeds the coolant from the sump 67 to a central oil supply 27. The coolant can be conveyed, for example, by the hydraulic pump that is already used to actuate the friction clutches 5, 6. Alternatively, a separate pump can be used for active conveyance, or a gear with a separator can be used for passive conveyance.

[0041] The central oil supply 27 has a feed channel 28 formed in the clutch housing 20. The feed channel 28 is designed as a radially extending channel through which the coolant, which is pumped here, flows from the radial outside to the radial inside. At the radially inner end of the feed channel 28, it opens into a collecting groove 29 of a deflection ring 30, which runs circumferentially around the rotational axis X. The deflection ring 30 is in the Figures 5 to 7shown in detail. The deflection ring 30 is inserted into a recess of the clutch housing 20 and largely seals the feed channel 28 to the side shaft 50. The deflection ring 30 is held stationary relative to the clutch housing 20 and has a central opening 31 for receiving the, here, right side shaft 50, with clearance. In a wall 32 axially delimiting the collecting groove 29 and extending in the circumferential direction, a plurality of transfer bores 33 are formed, which are distributed in the circumferential direction and aligned in the axial direction. Figure 7 It can be seen that the transfer bores 33 are located radially further inward than a bottom 34 of the collecting groove 29 and thus form a groove-shaped inlet area 35 in the area of ​​the collecting groove 29.

[0042] Arranged axially between the deflection ring 30 and the first inner disk carrier 3 is the right-hand cover 14, which is connected to the outer disk carrier 2 in a rotationally fixed manner. Formed in the cover 14 are a plurality of transfer bores 36, which are distributed in the circumferential direction and are axially aligned. A first rotary feedthrough 37 is provided to connect the transfer bores 33 to the transfer bores 36 in a fluid-conducting manner. The first rotary feedthrough 37 is formed by an axial projection 38 of the deflection ring 30 and by an annular space 39 of the cover 14 that is open towards the deflection ring 30. The annular space 39 is delimited radially between a radially outer wall 40 of the cover 14 and the surface of the right-hand side shaft 50. The deflection ring 30 projects into the annular space 39 with its axial projection 38.The transfer holes 33 of the deflection ring 30 and the receiving holes 36 of the cover 14 are arranged relative to one another in such a way that they are temporarily fluidically connected to one another at least once, here sixteen times, during one rotation of the cover 14 about the rotation axis X. Sixteen transfer holes 33 and sixteen receiving holes 36 are provided here purely as an example, although in principle more or fewer than sixteen holes can be provided in each case. Likewise, the number of transfer holes 33 can also differ from the number of receiving holes 36.

[0043] At an end facing the first inner disk carrier 3, the transfer bores 36 open into a first distribution channel 41 formed in the first inner disk carrier 3. The first distribution channel 41 is formed as an axially extending annular gap that is radially delimited by a radially inner channel wall 44 of the first inner disk carrier 3 and a radially outer channel wall 45 of the first inner disk carrier 3. The cover 14 has an axial projection 42 that projects into the first distribution channel 41 through a lateral inlet opening 43 of the latter. The inlet opening 43 is annular. The outer radius of the projection 42 is correspondingly smaller than the radial distance of the radially outer channel wall 45 from the rotational axis X.A second rotary feedthrough 51 is formed by the axial projection 42 of the cover 14 and the section of the first distribution channel 41 that axially overlaps the projection 42, in order to fluidly connect the transfer bores 36 to the first distribution channel 41. Specifically, the transfer bores 36 of the cover 14 exit through transfer openings 46 formed on an axial side of the cover 14 facing the first inner disk carrier 3. The transfer openings 46 are axially spaced from an end face 47 of the axial projection 42 and set back from it. Between the end face 47 and the front side, in which the transfer openings 46 are located, an annular space 48 is formed, through which the coolant is guided into the first distribution channel 41. The wall 40 of the cover 14 is chamfered in the region of the annular space 48, with the chamfer opening towards the first distribution channel 41.The channel wall 44 radially inwardly bounding the first distribution channel 41 is also chamfered, with the chamfer of the inner channel wall 44 running parallel to the chamfer of the wall 40 of the annular space 48. The transfer bores 36 extend radially further inward than the first distribution channel 41, so that the coolant flows into the first distribution channel 41 along the chamfered wall 40 due to centrifugal forces.

[0044] A surface of the radially outer channel wall 45 lies in an imaginary lateral surface that delimits the first distribution channel 41 radially on the outside. The lateral surface is frustoconical. In contrast, the radially inner channel wall 44 runs parallel to the rotational axis X. The distance of the radially outer lateral surface from the rotational axis X increases in the axial direction. In this way, the first distribution channel 41 widens radially outwards in the flow direction of the coolant. The flow direction is in Figure 2indicated by the arrow F. During operation of the dual clutch unit 1, the coolant is thus conveyed by the centrifugal force on the radially outer channel wall 45 through the first distribution channel to a second distribution channel 52. An opening angle α between the surface lines M of the lateral surface and the rotational axis X is, here, approximately 2°, wherein the opening angle α preferably opens in the flow direction F of the coolant, that is, in a direction towards the second distribution channel 52. In the Figure 2 the opening angle α between one of the generatrix lines M and the rotation axis X is shown using a parallel projection P of the rotation axis X.

[0045] Outlet openings 53 are formed in the radially outer channel wall 45 of the first distribution channel 41, which open into the outlet channels 25' in the first distribution channel 41. The outlet openings 53 are arranged in an imaginary spiral concentric with the rotational axis X. The diameter of the respective outlet openings 53 increases relative to one another in the flow direction F. Accordingly, the outlet opening 53 closest to the inlet opening 43 has the smallest diameter and the outlet opening 53 has the largest diameter. The diameter of the respective outlet channels 26 in the outer plate carrier 2 can also be designed accordingly in order to prevent a local undersupply, oversupply, or blockage of the coolant and lubricant. In particular, at least a subset of the outlet channels 26 along the first plate pack 7 can have a smaller diameter than at least a subset of the outlet channels 26 along the second plate pack 8.

[0046] The first distribution channel 41 opens into a plurality of through-bores 54 distributed in the circumferential direction. The through-bores 54 are formed in the first inner disk carrier 3. A longitudinal bore axis L of the respective through-bores 54 forms an angle with the rotation axis X that corresponds to the opening angle α. A plurality of recesses 55 spaced apart in the circumferential direction are provided in the radially outer channel wall 45 of the first distribution channel 41. The recesses 55 extend in the axial direction, with the recesses 55 beginning at the inlet opening 43 and each opening into one of the through-bores 54, here flush. The recesses 55 have a constant depth over their length. Four of the through-bores 54 and correspondingly four of the recesses 55 in the first inner disk carrier 3 are shown here purely as an example.

[0047] The through-bores 54 extend through an axial projection 56 of the first inner disk carrier 3, which projects into the second distribution channel 52 through an annular opening 49 of the second inner disk carrier 4, arranged concentrically to the rotational axis X. The second distribution channel 52 is formed as an axially extending annular gap delimited by a radially inner channel wall 62 of the second inner disk carrier 4 and a radially outer channel wall 57 of the second inner disk carrier 4. The outer radius of the projection 56 is smaller than the radial distance of the radially outer channel wall 57 of the second distribution channel 52 from the rotational axis X. The through-bores 54 emerge at an end face 58 of the axial projection 56 and thus open within the second distribution channel 52.The axial projection 56 of the first inner disk carrier 3 and the section of the second distribution channel 52 that axially overlaps the projection 56 thus form a third rotary feedthrough 59 for fluidly connecting the through-bores 54 to the second distribution channel 52. To seal the third rotary feedthrough 59 radially outward, a ring 61 is pushed onto the axial projection 56 of the first inner disk carrier 3. The second inner disk carrier 4 is supported axially on the first inner disk carrier 3 via the ring 61. The ring 61 can therefore also be referred to as a spacer. The ring 61 has a sliding surface and can, for example, be a bronze ring. The radially inner channel wall 62 of the second distribution channel 52 and an outer wall 63 of the projection 56 of the first inner disk carrier 3 facing the inner channel wall 62 have chamfers 64, 65 formed in opposite directions to one another.The chamfers 64, 65 are axially spaced from one another, the axial distance corresponding at least approximately to the thickness of the ring 61.

[0048] A surface of the radially outer channel wall 57, which radially delimits the second distribution channel 52 on the outside, lies in an imaginary lateral surface. The lateral surface, like that of the first distribution channel 41, is frustoconical. In contrast, the radially inner channel wall 62 runs parallel to the rotational axis X. In this way, the second distribution channel 52 also widens radially outward in the flow direction of the coolant. The flow direction is in Figure 2indicated by the arrow F. Due to the increasing distance of the radially outer surface from the rotational axis X in the axial direction, the coolant is conveyed through the second distribution channel 52 by the centrifugal force on the radially outer channel wall 62. The opening angle α between the surface lines M of the surface of the second distribution channel 52 and the rotational axis X and the opening angle α between the surface lines M of the surface of the first distribution channel 41 and the rotational axis X are, here, identical, i.e., approximately 2°. Both opening angles α open in the flow direction F of the coolant.

[0049] Outlet openings 66 are also formed in the radially outer channel wall 57 of the second distribution channel 52, which open into the outlet channels 25" in the second inner disk carrier 4. The outlet openings 66 are arranged on an imaginary spiral concentric with the rotation axis X. The diameter of the respective outlet openings 66 increases in the flow direction F. Accordingly, the outlet opening 66 closest to the annular opening 49 has the smallest diameter, while the outlet opening 66 furthest from the annular opening 49 has the largest diameter.

[0050] The second distribution channel 52 is closed at an end 68 facing away from the annular opening 49. Thus, upon rotation of the second inner disk carrier 4, the coolant flowing into the second distribution channel 52 can only leave it via the outlet channels 25" for lubrication of the second disk pack 8.

[0051] During operation, the coolant is conveyed from the sump 67 to the central oil supply 27, for example by means of an oil pump (not shown), and from there pumped radially inward through the feed channel 28 formed in the clutch housing 20. From the open end of the feed channel 28, the coolant flows into the collecting groove 29 of the deflection ring 30 and is axially deflected there through the axially aligned transfer bores 33. The coolant flows through the first rotary union 37 into the transfer bores 36 formed in the right-hand cover 14, which rotate about the rotational axis X upon rotation of the outer disk carrier 2. At the axial end of the transfer bores 36 facing the first inner disk carrier 3, the coolant flows through the second rotary union 51 into the first distribution channel 41.When the first inner disk carrier 3 rotates about the rotational axis X, the coolant is pressed against the radially outer channel wall 45 due to the centrifugal forces and flows through the axially widening first distribution channel 41 in a direction towards the through-bores 54. A first portion of the coolant passes through the outlet openings 53 arranged on the imaginary spiral into the outlet channels 25' to lubricate the first disk pack 7. A second portion of the coolant is fed directly to the through-bores 54 via the groove-like recess 55. Consequently, no outlet openings 53 for the outlet channels 25' are formed in the recess 55. The second portion of the coolant is thus pressed through the through-bores 54 via the third rotary feedthrough 59 into the second distribution channel 52.When the second inner disk carrier 4 rotates about the rotational axis X, the coolant is pressed against the radially outer channel wall 57 due to the centrifugal forces and flows through the second distribution channel 52, which widens in the axial direction, in a direction towards the closed end 68 of the second distribution channel 52. On the way there, the coolant flows through the outlet openings 66 arranged on the imaginary spiral into the outlet channels 25" to lubricate the second disk pack 8. Subsequently, upon rotation of the first inner disk carrier 3 or the second inner disk carrier 4, the coolant flows through the respective disk pack 7, 8 and reaches the radially outer end of the clutch chamber 13 through the outlet channels 26 formed in the outer disk carrier 2 back into the sump 67. For this purpose, the coolant flowing out of the outlet channels 26 can be directed onto a housing wall of the stationary clutch housing 20 into the sump 67. be derived.

[0052] The Figure 8 shows an enlarged partial section of a dual clutch unit according to the invention in a modified embodiment. This embodiment largely corresponds to that according to the Figures 1 to 7 , to whose description reference is made. Identical details are provided with the same reference numerals as in the Figures 1 to 7 . In the Figure 8 is to clarify the only difference compared to the embodiment according to the Figures 1 to 7 , here, the first inner disk carrier 3 is shown in detail.

[0053] It can be seen that the radially outer channel wall 45 of the first distribution channel 41 runs parallel to the axis of rotation X and thus also parallel to the radially inner channel wall 44 of the first distribution channel 41. Furthermore, an Archimedean screw 69 is inserted in the first distribution channel 41 and is connected in a rotationally fixed manner to the first inner disk carrier 3. By means of the Archimedean screw 69, according to the known principle of a screw pump, the coolant flowing into the first distribution channel 41 through the inlet opening 43 during operation of the dual clutch unit can be conveyed to the through-bores 54 upon rotation of the first inner disk carrier 3.

[0054] The Archimedean screw 69 is in the Figure 9, shown as a single component to clarify its structure. The Archimedean screw 69 has a cylindrical bore 70, so that the Archimedean screw 69 can be inserted through the inlet opening 43 into the first distribution channel 41. The inner diameter of the cylindrical bore 69 corresponds, at least approximately, to the outer diameter of the radially inner channel wall 44. The outer diameter of the Archimedean screw 69 corresponds, at least approximately, to the inner diameter of the radially outer channel wall 45. Chambers are formed between the individual blade sections of the Archimedean screw 69, in which the coolant can be screwed towards the through-bores 54. In this case, the coolant is also guided past the outlet channels 25', through which a portion of the coolant is guided into the clutch chamber 13 for lubrication of the first disk pack 8. Optionally, the Figures 1 to 7known recesses 55 together with the Archimedean screw 69.

[0055] In an analogous manner, the second inner disk carrier 4 can also have an Archimedean screw 69. In this way, upon rotation of the second inner disk carrier 4, the coolant flowing during operation from the first distribution channel 41 via the through-bores 54 into the second distribution channel 52 can be supplied to the outlet channels 25" in the second inner disk carrier 4 for lubrication of the second disk pack 8.

[0056] The Figure 10 shows an enlarged partial section of a dual clutch unit according to the invention in a further embodiment. This embodiment largely corresponds to that according to the Figures 1 to 7 , to whose description reference is made. Identical details are provided with the same reference numerals as in the Figures 1 to 7 . In the Figure 10is to clarify the only difference compared to the embodiment according to the Figures 1 to 7 , here, the first inner disk carrier 3 is shown in detail.

[0057] The first inner disk carrier 3 is distinguished by the fact that a plurality of first distribution channels 71 are provided. The first distribution channels 71 are designed as bores and are distributed circumferentially around the rotation axis X. The first distribution channels 71 extend from the inlet opening 43, shaped as an annular gap, to the individual through-bores 54. Each of the first distribution channels 71 opens into a through-bore 54 associated with the respective first distribution channel 71. Preferably, the pair of first distribution channel 71 and associated through-bore 54 forms a continuous bore with a common borehole longitudinal axis A. The respective borehole longitudinal axis A encloses an opening angle α with the rotation axis X, which in this case is approximately 2°. The opening angle α preferably opens in the flow direction F of the coolant, i.e., in a direction away from the inlet opening 43.At least one outlet channel 25' is provided in the first distribution channels 71. Preferably, each of the first distribution channels 71 has a plurality of outlet channels 25'. In particular, the outlet channels 25' are arranged in an imaginary spiral across all first distribution channels 71. The outlet channels 25' can be aligned radially or skewed to the rotation axis X. Optionally, the outlet channels 25' from the embodiment according to FIGS. Figures 1 to 7 known recesses 55 in the individual first distribution channels 71 are used to convey a portion of the coolant past the outlet channels 25' to the through holes 54.

[0058] In an analogous manner, the second inner disk carrier 4 can also have a plurality of bores distributed in the circumferential direction around the rotational axis X, which form the second distribution channels. The second distribution channels are then, like the second distribution channel 52 according to the Figures 1 to 7shown embodiment, closed at the ends 68 facing away from the first inner disk carrier 3. Thus, upon rotation of the second inner disk carrier 4, the coolant can only flow out of the second distribution channels into the second disk pack 8 via the outlet channels 25". List of reference symbols

[0059] 1Dual clutch unit 2Outer plate carrier 3Inner plate carrier 4Inner plate carrier 5Friction clutch 6Friction clutch 7Disk pack 8Disk pack 9Pressure plate 10Pressure plate 11Support element 12Support element 13Clutch chamber 14Cover 15Cover 16Opening 17Opening 18Actuator unit 19Actuator unit 20Clutch housing 21Piston 22Cylinder chamber 23Opening 24Return spring 25Outlet channel 26Drain channel 27Central oil supply 28Feed channel 29Collecting groove 30Deflection ring 31Opening 32Wall 33Transfer bore 34Bottom 35Inlet area 36Transfer bore 37First rotary union 38Protrusion 39Annular space 40Wall 41First Distribution channel 42Protrusion 43Inlet opening 44Inner channel wall 45Outer channel wall 46Transfer opening 47End face 48Annular space 49Annular opening 50Side shaft 51Second rotary union 52Second distribution channel 53Outlet opening 54Through hole 55Recess 56Protrusion 57Outer channel wall 58End face 59Third rotary union 60Side shaft 61Ring 62Inner channel wall 63Outer wall 64Bevel65Bevel 66Outlet 67Sump 68End 69Archimedean screw 70Bore 71Distribution channel αOpening angle ABorehole longitudinal axis FFlow direction LBorehole longitudinal axis MMerge line PParallel projection XRotation axis

Claims

1. Dual clutch unit for variable torque distribution on two output shafts, comprising: an outer disk carrier (2) rotationally driven about a rotation axis (X), a first inner disk carrier (3), a first disk pack (7) for torque transmission between the outer disk carrier (2) and the first inner disk carrier (3), a second inner disk carrier (4), wherein the first inner disk carrier (3) and the second inner disk carrier (4) are arranged rotatably relative to each other about the rotation axis (X), a second disk pack (8) for torque transmission between the outer disk carrier (2) and the second inner disk carrier (4), wherein the dual clutch unit further comprises: a central oil supply (27) to supply the first disk pack (7) and the second disk pack (8) with coolant, a first distributor channel (41) being formed in the first inner disk carrier (3) and comprising a feed opening (43) through which the first distributor channel (41) is fluidly connected to the central oil supply (27), a second distributor channel (52) being formed in the second inner disk carrier (4) and being fluidly connected to the central oil supply (27) via the first distributor channel (41), and drain channels (25) being formed in the first inner disk carrier (3) to conduct the coolant into the first disk pack (7) and in the second inner disk carrier (4) to conduct the coolant into the second disk pack (8), and the first inner disk carrier (3) comprises at least one through-bore (54) through which the second distributor channel (52) is fluidly connected to the first distributor channel (41), characterised in that a borehole longitudinal axis (L) of the at least one through-bore (54) encloses a bore angle (α) with the rotation axis (X).

2. Dual clutch unit according to claim 1, characterised in that the first inner disk carrier (3) comprises an axial protrusion (56) with the at least one through-bore (54), wherein the protrusion (56) projects into the second distributor channel (52) and the second distributor channel (52) is designed as an axially extending annular passage at least in a region of axial overlap with the protrusion (56).

3. Dual clutch unit according to claim 1 or 2, characterised in that the bore angle (α) is between 0.01° and 10°.

4. Dual clutch unit according to one of claims 1 to 3, characterised in that guiding means (55) are formed in the first distributor channel (41) for guiding a partial quantity of the coolant towards the at least one through-bore (54).

5. Dual clutch unit according to claim 4, characterised in that the guiding means comprise at least one elongated recess (55) extending over at least 20% of the axial longitudinal extension of the first distributor channel (41) and opens into the at least one through-bore (54).

6. Dual clutch unit according to one of claims 1 to 5, characterised in that the first inner disk carrier (3) and the second inner disk carrier (4) are axially supported against each other.

7. Dual clutch unit according to one of claims 1 to 6, characterised in that the first distributor channel (41) and / or the second distributor channel (52) are each / is designed as an annular passage extending in the axial direction and being concentrically arranged to the rotation axis (X).

8. Dual clutch unit according to one of claims 1 to 7, characterised in that in a radially outer channel wall (45) of the first distributor channel (41) and in a radially outer channel wall (57) of the second distributor channel (52) outlet openings (53, 66) are formed which lead to the drain channels (25), wherein the outlet openings (53, 66) are arranged on an imaginary spiral arranged concentrically to the rotation axis (X).

9. Dual clutch unit according to one of claims 1 to 8, characterised in that an envelope surface delimiting the first distributor channel (41) radially outside and / or an envelope surface delimiting the second distributor channel (52) radially outside are / is designed frustoconically.

10. Dual clutch unit according to claim 9, characterised in that an aperture angle (α) between envelope lines (M) of the respective envelope surface and the rotation axis (X) is between 0.01° and 10° and that the respective aperture angle (α) opens in flow direction (F) of the coolant.

11. Dual clutch unit according to one of claims 1 to 10, characterised in that a deflector ring (30) is fluidly connected on its inlet side to the central oil supply (27) and on its outlet side to the first distributor channel (41), wherein the deflector ring (30) has a collecting groove (29) being circumferentially open and a plurality of transfer bores (33), which are circumferentially distributed and at least substantially axially aligned and fluidly connected to the collecting groove (29).

12. Dual clutch unit according to claim 11, characterised in that a cover (14) is non-rotatably arranged laterally on the outer disk carrier (2) and has a plurality of takeover bores (36), which are circumferentially distributed about the rotation axis (X) and fluidly connected to the first distributor channel (41), wherein the takeover bores (36) of the cover (14) and the transfer bores (33) of the deflector ring (30) are arranged relative to each other such that during each revolution of the cover (14) about the rotation axis (X) the transfer bores (33) and the takeover bores (36) at least once are temporarily fluidly interconnected with each other.

13. Dual clutch unit according to claim 12, characterised in that the cover (14) of the outer disk carrier (2) projects into the first distributor channel (41) providing a rotary transmission leadthrough (51) between the takeover bores (36) of the cover (14) and the first distributor channel (41) of the first inner disk carrier (3).

14. Drive assembly for driving a drive axle of a motor vehicle, comprising: a driving machine with a motor shaft, two output shafts (50, 60) arranged concentrically to each other and a clutch unit (1) arranged in a power path between the drive engine and the two output shafts (50, 60), characterised in that the clutch unit is a dual clutch unit (1) according to one of the claims 1 to 13, wherein the motor shaft rotatingly drives the outer disk carrier (2), and wherein a first output shaft of the two output shafts (50) is non-rotatably connected to the first inner disk carrier (3) and a second output shaft of the two output shafts (60) is non-rotatably connected to the second inner disk carrier (4).